Atomic movement during the oxidation of GaAs

A new technique is developed to study the atomic movement in ultraviolet laser enhanced and low temperature (≤ 400 ° C) thermal oxidation of GaAs. The new method is a combination of the classical marker technique and low energy ion scattering spectroscopy (ISS). In the formation of thin GaAs oxide layers (∼ 10 Å), the marker is found to remain on the oxide surface, indicating that oxidation is occurring at the intrface of GaAs/oxide by the diffusion of an oxygen species. This is in contrast to the oxidation of metals such as Ni and Cu where the same technique supports earlier observations that oxidation occurs at the oxide/ambient interface. The diffusion of a metal species results in the marker being buried during the oxidation of the metal surfaces.